Cylinder lock



P. W. OLSON CYLINDER LOCK May '8, 1945.

Filed April 8, 1943 n W PW y Y. a

PW 11/. azs BY Patented May 8, 1945 UNITED STATES PATENT OFFICE, h g2,375,682

. CYLINDER were Phillip W. Olson, Chicago, 111.. Application April s,1943, Serial No. 482,346

2 Claims. This invention relates in general to looks and moreparticularly to a tumbler type cylinder lock highly resistant to.picking.

So-called pick-proof locks prior to this invention usually weredependent upon a large number of tumblers or other complicated means ifor their securityiand resistance to picking, which construction isexpensive, whereas the novel construction of the present inventionincludes simple means whereby the use of relatively few tumblers andcorrespondingly low manufactuing cost provide ample security and highdegree ofresistance to picking.

Ihe principal object of the invention is to provide a tumbler lockincluding a plurality of relatively few detent-controlled tumblers.

A further object of the invention is the provision of a cylinder lockhaving detent-controlled.

i 9 Further object and advantages of the invention will be apparentinone embodiment hereinafter described, in which: 7

Fig. 1 is a side elevation of the lock assembly. Fig. 2 is a typical keyfor operating the lock shown Fig. 1. i

Fig, 3 is an enlarged cross-sectional view of the lock taken throughsection lines 33, Fig. 1.

Fig. 4 is. an enlarged cross-sectional View of the key takenthroughsection lines 4-4, Fig. 2.

Fig. 5 is an enlarged perspective view of the tumbler elements of thelock.

Fig. 6 is an enlarged cross-sectional elevation of the lock takenthrough section lines 6-6, Fig. 3 and showing the key in proper relationto the For the purpose of illustration, the type lock shown anddescribedis for the use of a key having unrelated serpentine grooves in itsoppo-. site sides, and although this showing is a preferredconstruction, it will appear from the following description that locksfor other type keys are equally applicable. i

Referring to Fig. 1, the barrel or housing I serves to retain theelements of the lock. .A cap 2 closely fitted over the barrel containsthe keyhole. A conventional bolt 3 is integrally secured to therotatable cylinder 4 and is adapted to engage a strike plate, not shown.

Referring to Figs. 2 and 4, the key 5 is provided with a rectangularshank 6 having unrelated sernormally would unlock the bolt 3 from astrike pentine grooves l in each side thereof. The barrel I has in'itsinside periphery, two pair of oppositely disposed grooves 8 runningparallel to its axis.

A cylinder 4 is constructed of two half sections and held together bymeans of two snap rings 9 fitting in appropriate grooves in each end ofthefcylinder, shown in Fig. 6. The cylinder is adapted to rotate freelywithin the barrel l. A cylindrical projection ll! of the cylinderextends through a bearing ring I l which is retained in proper positionby a snap ring 12. The bolt 3 is integrally attached to the end of theprojection t In for locking purposes.

Referring to Fig. 5, each tumbler I3 is provided with a detentprojection l4 and a key follower 15 positioned opposite the detent. Thekey follower in each tumbler is positioned to correspond with apredetermined formation of the serpentine grooves I in the keyptheaction of which will be hereinafter described. Each tumbler is placed inits corresponding slot IS in the cylinder 4 which extends through thecylinder at right angles to the axis of rotationof the cylinder.

A detent plunger IT having a Pointed end and a spring IB are retained inthe cylinder in an appropriate hole IS. The pointed end of the plungeris adapted to slidably engage the detentv projection M of eachcorresponding tumbler.

It is now apparent from Fig. 3 that each tumbler is capable ofreciprocable movement in its slot l6 and that the plunger I! will urgethe tumblerv in either direction depending upon its initial movementover the central point of the projection.

In operation and assuming that the key followers l5 have been positionedto suit a corresponding key, it will be seen from Fig. 6 that one end ofeach tumbler will engage a groove 8 and thus prevent the cylinder 4 fromturning in the barrel 1. When the key shown in Fig. 6 is inserted, thelateral surfaces of the serpentine groove 1 will engage the keyfollowers l5 and Withdraw each tumbler a predetermined distance to freeits end from the grooves 8 and thus enable the key to turn the cylinder4 within the barrel I, which plate.

The usual practice of picking locks i dependent upon either vibrating ormoving the tumblers and disengaging their ends from locking grooves. Inthe present invention any attempt at moving the tumblers topredetermined positions would be defeated by virtue of the detent actionpreviously described, as it can easily be i seen if a particular tumbleris withdrawn sufficiently far to disengage one of its ends from thecylinder groove and the plunger l1 reaches the peak of the projection Mof the tumbler, the plunger, urged by spring l8, will throw the tumblerin the opposite direction and thus engage the opposite end of thetumbler in the groove of the cylinder. Therefore, any attempt to operateor pick even a small plurality of tumblers without a key is impracticalif not impossible.

Although the lock described herein shows three tumblers, it is to beunderstood that a smaller or larger number of tumbler may be usedwithout departing from the scope of the invention.

Having described my invention, I claim: 1. A cylinder lock comprising acasing having a'key-operable rotatable cylinder afiixed therein, saidcasing having a plurality of tumbler slots therein, a plurality ofkey-operable tumblers slidslots, each'said tumbler provided with anintegral detent projection, spring-actuated detent means for normallyand independently engaging said therein, a plurality of key-operabletumblers slidably retained in saidcylinder, each end of said tumblersadapted to engage corresponding said bler in a corresponding said slotto lock said cyl-- inder to said casing.

- PHILLIP W. OLSON.

